In a process for producing a fluoropropene by fluorinating a halopropane or a halopropene as a starting material with hydrogen fluoride, the reactions proceed in the route as described below when 1,1,1,2,3-pentachloropropane is fluorinated in a gas phase.CCl3CHClCH2Cl+3HF→CF3CCl═CH2+4HCl  (1)CF3CCl═CH2+HF→CF3CF═CH2+HCl  (2)
In these reactions, the reaction rate in the reaction for producing 2-chloro-3,3,3-trifluoropropene from 1,1,1,2,3-pentachloropropane (first reaction) is significantly different from that in the reaction for producing 2,3,3,3-tetrafluoropropene from 2-chloro-3,3,3-trifluoropropene (second reaction). Thus, it is inefficient to perform these reactions using a single reactor, and it is ideal to perform the reactions using separate reactors. For example, Patent Literature 1 listed below discloses a process in which fluorination is performed in a gas phase in three steps under conditions according to each reaction, using three reactors packed with different catalysts. Patent Literature 2 listed below discloses an integrated process using these reactions.
However, in these processes, it is difficult to obtain 100% conversion in each reaction, and it is necessary to separate the unreacted starting materials and the target product from the reaction mixture to recycle the unreacted starting materials. In such a case, the separation of the product from the reaction mixture is typically performed using a distillation column, and it is required to cool the reaction gas heated to several hundred degree Celsius and separate the unreacted starting materials using a distillation column. Thereafter, the product thus obtained are gasified by reheating and supplied to the next rector. Performing this operation in each of reaction steps results in significant energy loss. In addition, the number of distillation columns required for the separation is increased, leading to an increase in equipment costs.